As a result of the prosperity and progress of the present industrial and commercial activities, the flush toilet has become indispensable in homes and apartments. The use of a large number of toilets, many of which are flushed many times everyday has caused a serious water supply problem, especially during energy crisis periods; the water being an expensive commodity. Now, all conventional flush toilets are usually operated by pressing a lever, which pulls a chain or the like to open a water outlet permitting water to flow from a tank for flushing. Usually, the water level in the water tank is controlled with a ball buoy. Whenever pressing the lever once, a volume of several liters of water will be flushed away; such case would be considered a waste during only releasing a urine. By the rate of flushing decades of liters of water each day, the volume of water to be flushed by the people of the whole world would be a surprising figure.
In case of a drought season appearing, water crisis will be resulted. Further, in the conventional flush toilet, the chain in the water tank is liable to be broken because of daily pulling tension to cause the lid unable to tightly close the water stop outlet; consequently, a water leak, which is another way of wasting the water, often results in addition to often required repair work. It is apparent that the conventional flush toilet is not practical in use because of wasting water. Moreover, the water stop lid in the conventional flush toilet is made of rubber in conic shape and hollow in its core; it is usually pulled with a cord to flush the water, and also is liable to cause a leak from the rift as a result of a loosing cord; therefore, it may be deemed as a bad product.